change due to delta: -0.7 x 5 x 40,000 x (0.695 - 0.643) = -7280gamma = 2.5 contracts per dollar = 100,000 lbs of cattle per dollarso change due to gamma: 1/2 x 100,000 x (.695 - 0.643)^2 = 135.20 total instantaneous change in MTM assuming no change in implied vol: 135.20 minus 7280 = -7144.80